A variation of Sternberg\u27s paradigm

An investigation was carried out to test Sternberg’s stage theory using his additive-factor method. Three factors were proposed that would have additive effects on RT and two factors that would not. Ss were presented stimuli in the form of colors and sound frequencies under varying combinations of mode, stimulus quality, list length, and response type. Ss were also blocked according to sex. Results revealed only stimulus quality and list length to be additive. Response type interacted with list length. Males were faster than females but the sex factor was differentially influencing two of the proposed stages in Sternberg’s model. The experiment failed to find any differences between the auditory and visual modes. In light of the present findings a re-evaluation of Sternberg’s model was discussed

Effects of Universal Extra Dimensions on Higgs signals at LHC

A major focus at the Large Hadron Collider (LHC) will be Higgs boson studies and it would be an interesting prospect to simultaneously probe for physics beyond the Standard Model (SM) in the Higgs signals. In this work we show as to what extent, the effects of Universal Extra Dimension (UED) can be isolated at the LHC through the Higgs signals. By doing a detailed study of the different uncertainties involved in the measurement of the rates for the process pp --> h --> gamma gamma we estimate the extent to which these uncertainties can mask the effects of the contributions coming from UED.Comment: 13 pages, LateX, Title changed, text and figures modified. Version to appear in IJMP

Distribution of periodic points of polynomial diffeomorphisms of C^2

This paper deals with the dynamics of a simple family of holomorphic diffeomorphisms of \C^2: the polynomial automorphisms. This family of maps has been studied by a number of authors. We refer to [BLS] for a general introduction to this class of dynamical systems. An interesting object from the point of view of potential theory is the equilibrium measure $\mu$ of the set $K$ of points with bounded orbits. In [BLS] $\mu$ is also characterized dynamically as the unique measure of maximal entropy. Thus $\mu$ is also an equilibrium measure from the point of view of the thermodynamical formalism. In the present paper we give another dynamical interpretation of $\mu$ as the limit distribution of the periodic points of $f$

Akt/PKB Controls the Activity-Dependent Bulk Endocytosis of Synaptic Vesicles

Activity-dependent bulk endocytosis (ADBE) is the dominant SV endocytosis mode during intense neuronal activity. The dephosphorylation of Ser774 on dynamin I is essential for triggering of ADBE, as is its subsequent rephosphorylation by glycogen synthase kinase 3 (GSK3). We show that in primary cultures of cerebellar granule neurons the protein kinase Akt phosphorylates GSK3 during intense neuronal activity, ensuring that GSK3 is inactive during intense stimulation to aid dynamin I dephosphorylation. Furthermore, when a constitutively active form of Akt was overexpressed in primary neuronal cultures, ADBE was inhibited with no effect on clathrin-mediated endocytosis. Thus Akt has two major regulatory roles (i) to ensure efficient dynamin I dephosphorylation via acute activity-dependent inhibition of GSK3 and (ii) to negatively regulate ADBE when activated in the longer term. This is the first demonstration of a role for Akt in SV recycling and suggests a key role for this protein kinase in modulating synaptic strength during elevated neuronal activity

Functional Impulsivity as a Psychometric Manifestation of the Behaviour Activation System: a Contribution to the Solution of the 'Impulsivity Problem'.

The Reinforcement Sensitivity Theory (RST) view of personality has for many years related impulsivity to the Behaviour Activation System (BAS), a neurobiological network mediating appetitively motivated approach of reward. The wider literature however suggests that there are many varied manifestations of impulsivity, and it is not clear how these traits are to be reconciled with - or distinguished from - RST. Dickman (1990) has suggested that there are two principal forms of impulsivity; 1) dysfunctional impulsivity, which captures the traditionally negative view of this trait as failing to 'look before you leap', which seems unrelated to the RST view; and 2) functional impulsivity, which reflects the potential benefits of acting quickly, and which we argue is theoretically consistent with proposed manifestations of the BAS. In our first study, we investigate the relationship that Dickman's impulsivity scales have with measures of both RST and personality in general. We concluded that functional impulsivity may provide a useful psychometric measure of BAS, whereas dysfunctional impulsivity seems unrelated to RST. In our second study we use a go/no-go paradigm to confirm our conclusions empirically. Results indicated that functional impulsivity, along with two purpose-built BAS measures from the literature, was a significant predictor of increased responding to reward. In comparison, dysfunctional impulsivity predicted increased responding irrespective of whether responses were rewarded or punished. We discuss the significance of our findings to RST specifically, and personality research overall, concluding that this research compliments but theoretically refines Dickman's (1990) dichotomization of impulsivity

Dimension of the Torelli group for Out(F_n)

Let T_n be the kernel of the natural map from Out(F_n) to GL(n,Z). We use combinatorial Morse theory to prove that T_n has an Eilenberg-MacLane space which is (2n-4)-dimensional and that H_{2n-4}(T_n,Z) is not finitely generated (n at least 3). In particular, this recovers the result of Krstic-McCool that T_3 is not finitely presented. We also give a new proof of the fact, due to Magnus, that T_n is finitely generated.Comment: 27 pages, 9 figure

Next-to-leading order multi-leg processes for the Large Hadron Collider

In this talk we discuss recent progress concerning precise predictions for the LHC. We give a status report of three applications of our method to deal with multi-leg one-loop amplitudes: The interference term of Higgs production by gluon- and weak boson fusion to order O(alpha^2 alpha_s^3) and the next-to-leading order corrections to the two processes pp -> ZZ jet and u ubar -> d dbar s sbar. The latter is a subprocess of the four jet cross section at the LHC.Comment: 6 pages, 5 figures. Talk given at the 8th international Symposium on Radiative Corrections (RADCOR), October 1-5 2007, Florence, Ital

On the shoulders of giants

British psychologists such as Hans Eysenck and Jeffrey Gray have been giants in the field of individual differences, offering psychobiological accounts of major personality traits such as extraversion and neuroticism, as well as the cluster of impulsive antisocial sensation-seeking personality facets, marked by Eysenck's psychoticism scale. These theories have stimulated vibrant research programmes worldwide, including several within British psychology departments. This article provides a snapshot of classic and contemporary British research into the affective, behavioural and cognitive processes which characterise personality

Geometry, topology and dynamics of geodesic flows on noncompact polygonal surfaces

We establish the background for the study of geodesics on noncompact polygonal surfaces. For illustration, we study the recurrence of geodesics on $Z$-periodic polygonal surfaces. We prove, in particular, that almost all geodesics on a topologically typical $Z$-periodic surface with boundary are recurrent.Comment: 34 pages, 13 figures. To be published in V. V. Kozlov's Festschrif